Abstract Purpose of Review Problematic pornography use (PPU) describes a pattern of behavior characterized by excessive time spent using or thinking about pornography and continued use despite negative consequences. To help advance the understanding of transdiagnostic underlying psychological and neurobiological mechanisms in PPU, we aim to review existing evidence on these mechanisms focusing on positive valence systems within the transdiagnostic Research Domain Criteria (RDoC) framework. Recent Findings Reward anticipation processes seem to be increased in individuals with PPU symptoms when they anticipate sexual stimuli compared with other rewards. Studies further suggest that the initial neural and attentional responses to sexual rewards compared with different control stimuli are also increased in individuals with PPU symptoms, as are conditioned responses in sexual reward learning paradigms. Sexual reward valuation studies point towards an increased neural value differentiation with increasing PPU symptoms. Summary The current state of evidence indicates that positive valence systems are altered in persons with PPU. This framework of organizing evidence may aid in elucidating PPU development and maintenance as well as planning future studies.